Wikipedia:Reference desk/Archives/Science/2008 March 23

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[edit] March 23

[edit] Trying to recall something I read years ago

Dear Wikipedians:

I need your help in discerning a passage that I read years ago but one which I couldn't find anymore. It is related to the role technology plays in medicine.

What I can remember of the passage are as follows (italics means specific details that I can no longer remember, bold means key texts that I knew definitely appeared in the passage that I read):

“ Take the disease disease name (tuberculosis?) for example, in the 1950s there were great debates about the construction of hospitals that are specifically geared to the treatment of patients with the disease, there are back-and-forth arguments in leading medical journals about the quarantine measures, treatment processes, people couldn't even seem to agree on the a treatment process, and the case study of a girl's name, girl is an African-American.

But then the wonder-tech-gizmo-drug (an antibiotic?) was discovered. And it proved to be so effective in treating disease name, that talks of building hospitals also soon died down.

 ”

Thanks.

76.68.9.59 (talk) 00:16, 23 March 2008 (UTC)

Well, just judging from the dates (1950s), the fears of the epidemics and the importance of the drug, my guess would be that the disease is polio, and that the wonder drug was the Salk vaccine. But this is a wild-guess—lots of antibiotics and vaccines were developed in the 1950s to treat all sorts of things, though the Salk/polio case is one of the most famous. No clue about the case study. --Captain Ref Desk (talk) 04:54, 23 March 2008 (UTC)
But the circumstances seem to fit TB much better. Sanitoriums were actually constructed when the only treatment for the disease was isolation and bedrest; the first antitubercular drug, streptomycin, was discovered in 1943, with the discovery first published in 1947. The discovery was followed by that of para-aminosalicylic acid, and by isoniazid (the wonder drug) in 1952. It became evident that bedrest wasn't important, and sanitarium construction stopped, and existing sanitaria were "repurposed". But I don't know what case study you might be talking about. You may be interest in this article on the history of tuberculosis. - Nunh-huh 11:36, 23 March 2008 (UTC)
The only other institutions I can think of that were "shut-down" as a result of improved medical treatment were "insane asylums", but this was in the 1970s and later. - Nunh-huh 11:47, 23 March 2008 (UTC)
"Insane asylums" became "psychiatric institutions" in the 1940s. Deinstitutionalization was already in play long before the first anti-psychotics were developed, though (which was in the 1950s as well—see thorazine). It's not so much that state care of the mentally ill went away so much as it decentralized. (The dismantling of the American mental health system by Reagan actually had its roots much earlier, as people for decades felt that centralized state institutions were prone to abuse and waste that local, county or community based care was not.) --Captain Ref Desk (talk) 19:56, 23 March 2008 (UTC)
As highlighted by the above discussion, given the importance of the date range in trying to answer this, how sure are you of it? For example, if it could have been like the 1930s that would be different from if it could have been in the 1970s. The example that I can think of that best fits your text to me is leprosy. Leper colonies were of cause not uncommon in the past and I would presume there they are something often debated by the medical community once it was established. As discussed in both the linked articles, it appears to me they are generally no longer considered medically necessary by most of the medical establishment because of both the widespread availability of effective treatments and the fact that leprosy is not nearly as contagious as people believe/d. The dates on this don't really agree with your 1950s, treatments were available in the early 1940s but they weren't that effective and it was only in 1982 that an effective (multidrug) treatment was developed which combined with the acceptance that leprous was not that communicable lead to the decline of leper colonies. Leper colonies weren't of course specific hospitals but segregated communities which is another area where this doesn't fit your memory. Also the case study seems a bit iffy since it doesn't seem that the US led the way in leprosy research. Actually um ignore my example, the more I think of it, the more it doesn't fit, since you're fairly sure of the last sentence but leper colonies aren't hospitals and already existed and had for a long time, it doesn't really fit... I believe HIV was a major scare as well with suggestions for quarantine (Cuba at least put this into practice IIRC but are now consider a shining star in the fight against HIV) but that was even latter and it hasn't been beaten, it's just well understood enough that people know quarantine serves little purpose Nil Einne (talk) 17:23, 23 March 2008 (UTC)


Thank you all for your response. I can now remember it as being TB + Streptomycin. Thank you sooooooooooo much! 76.65.14.58 (talk) 23:06, 23 March 2008 (UTC)

[edit] Long-term effects of 0 g

The ISS, that beautiful star in the sky, is coming down in a few short years. Hardly completed as of yet, it will be scrubbed before 2020. I would ask for some imagination from all you readers. Some horrible tragedy inflicts the Earth below. Just for a moment, let us pretend the ISS will maintain its position as a star in our sky for many decades to come, constantly replenished, that our species will continue to inhabit the night's sky. Here's what I would like to know: If I were a crew member on the station (I am a 31 y.o. healthy male), what would happen to me if I were forced to spend a continued twenty or thirty years aboard? Could I survive? Sappysap (talk) 01:02, 23 March 2008 (UTC)

Quick answer, no one really knows the long term effects of extreme long term weightlessness since it has never been done before. However given the importance of understanding this, a lot of studies and theorising has gone on which I'm sure you could find. Human adaptation to space and weightlessness are good starting points. BTW, if something happened to earth, the people on the ISS would I'm pretty sure be screwed. It is not designed and probably isn't capable of independently supporting a human population in the long term amongst other things, they need food from earth. Also, if it's design lifespan is 10+ years, it could probably be extended by say 300-500% but I suspect no longer and even then, probably only with the support of earth. And given the tiny number of people on the ITN, presuming there are even 2 fertile people of the opposite sex on the ISS at the time something happens to earth, the human species will likely be screwed due to the inbreeding depression from the extreme inbreeding that would occur. (Not to mention the ISS would have a very limited population maximum even if it were completely self sufficient so the human species couldn't exactly 'thrive' there) Nil Einne (talk) 02:39, 23 March 2008 (UTC)
Additionally, the ISS would deorbit by itself within maybe 5 years due to air resistance. Icek (talk) 14:20, 23 March 2008 (UTC)
I should mentioned though that some of the studies/theorising may not quite cover what you are suggesting. Most commonly people analyse this from a 'trip to Mars' kind of POV or perhaps colonies on other planets like Mars or the moon (or others). These are not microgravity environments and even if the hope is for the colonies to be capable of being independent (which often doesn't mean an expectation of reproduction in the colonies in the short term), in general no one expects the colonies to be cut off from earth. And people tend to look at fairly long term, but not permanent existance in microgravity (since for all the reasons already explained and more even if we do want a colony capable of surviving without earth, we wouldn't build it in space). What all this means is that most studies consider it important that the people are capable of re-adjusting to life on earth which is one of the biggest problems with people adapted to microgravity environments (or even a lesser gravity environment) but if I understood your question correctly, this doesn't matter for your case. Nil Einne (talk) 16:49, 23 March 2008 (UTC)
WHAT??? The ISS is about to deorbit? Wouldn't that mean that it will impact the Earth like an asteroid? Isn't there anything to prevent this? Or will a shuttle retrieve the astronauts and allow the ISS to deploy safely? Or is there something I misunderstood? Thanks. ~AH1(TCU) 18:13, 23 March 2008 (UTC)
At the height of the ISS - currently approximately 340 km - typical objects deorbit within a few years (that also depends on the ratio of mass/(area perpendicular to velocity vector) of the object), at 600 km (about the height of the Hubble Space Telescope) it's maybe a few decades. Go to Heavens-Above and click on "Height of the ISS" - there you can see that the height constantly decreases, only to be increased by a boost (which consumes fuel of which there is not much on the ISS) every month or so. The ISS will impact the Earth, but slower than an asteroid would, with only about 8 km/s. They will steer it to an uninhabited region like the southern Pacific, as they did with Mir. Icek (talk) 19:18, 23 March 2008 (UTC)
Hi. Wow. The ISS is the most expensive object ever built by mankind. Well at least it's likely to break up in midair. Thanks. ~AH1(TCU) 00:15, 24 March 2008 (UTC)
Can we get a citation for the "scrubbed before 2020" part? Our ISS article doesn't mention anything about abandonment. —Steve Summit (talk) 00:22, 24 March 2008 (UTC)
well, basically, longterm exposure to zero g makes you gradually deteriorate, even if you exercise. the occasional collapses of shuttle pilots after landing, for instance. you also get sort of ballooned out in your upper body and head, as the fluid doesn't pool in your legs; folks in zero g always look kind of moonfaced. Gzuckier (talk) 18:51, 25 March 2008 (UTC)

[edit] "Jumping" of blood vessels around the eye

Hi. What's the medical term for the pulsating of the blood vessel right below the eye (in the eyebag for those with one)? Thanks. Imagine Reason (talk) 01:09, 23 March 2008 (UTC)

Blepharospasm -- —Preceding unsigned comment added by 79.76.201.53 (talk • contribs)

I don't mean the eyelid. It's more of the nerve or blood vessel under the eye (like at the bottom of the eye socket). Imagine Reason (talk) 02:03, 23 March 2008 (UTC)
Read the article fully. -- —Preceding unsigned comment added by 79.76.201.53 (talk • contribs)
Why should he read it thoroughly? Blepharospasm is unrelated to pulsating blood vessels, and accordingly, the article contains no mention of blood vessels, arteries, veins, or capillaries. Mark this one "unanswered". - Nunh-huh 11:28, 23 March 2008 (UTC)
Blood vessels dont pulsate like that and if they did you would not be able to feel it unless there were nerves in the vicinity. Its obvious you havent read the article Blepharospasm either!
I quote from the symptoms para;
Uncontrollable tics or twitches of the eye muscles and surrounding facial area. Some sufferers have twitching symptoms that radiate into the nose, face and sometimes, the neck area. Mark this one as answered by me!
OK, we'll count you as one satisfied answerer. Of some question.- Nunh-huh 14:46, 24 March 2008 (UTC)

[edit] can someone identify this flower for me?

It's a picture of a white flower with a grassy three-sided stem that grows from some tiny bulbs from underneath the grass every spring. The flowers are wrapped in a onion peal like matter before the petals spout out. the flowers smell like onions. Several flowers spout from one little area. This is in Richmond, California in Contra Costa County, California in the United States.Carritotito (talk) 02:22, 23 March 2008 (UTC)

Breaks easily when pulled? Probably onion weed[1]? Aka Asphodelus fistulosus. Our article doesn't have the same variety in the pic. Julia Rossi (talk) 03:05, 23 March 2008 (UTC)
I know Asphodelus fistulosus fairly well, and this is definitely not what you have. Asphodel has its flowers in an open panicle (spike-like), whereas all the true onions (genus Allium) have their flowers in an umbel (all flowers arise from the same point at the top of the stem). Your photo shows an umbel. If it smells like onion, it probably is an onion; there are many species of Allium native to California, plus a few noxious introduced species. The Jepson Manual (1993) lists 47 species native to California and four introduced.--Eriastrum (talk) 15:47, 23 March 2008 (UTC)
I think that I have figured out what species this is: Allium triquetrum, or Three-cornered garlic. It is native to the Mediterranean, but has naturalized in parts of California.--Eriastrum (talk) 17:35, 27 March 2008 (UTC)

[edit] Science+nutrition

What vitamin and/or nutrient does alcohol deplete from the human body?

Calcium uptake is most severely diminished with alcohol abuse, for example. In general, as you destroy your bowel's ability to take up nutrients, all those taken up after the stomach are affected more or less. Of course, the lungs an the brain, too. --85.179.15.63 (talk) 07:29, 23 March 2008 (UTC)
B Vitamin deficiency – but I can't figure where to show you except in the article Korsakoff's syndrome – an extreme example that doesn't seem to explain how this happens Julia Rossi (talk) 08:17, 23 March 2008 (UTC)
There are two proposed mechanisms of thiamine deficiency in alcoholics: [1] diminished intestinal absorption of thiamine caused by alcohol, and/or [2] destruction of thiamine by acetaldehyde. There are many other nutritional implications of alcoholism as well. Alcohol inhibits fat absorption, and thus interferes with absorption of vitamins A, D, & E. VItamin C & K are often deficient, which together with impaired hepatic function and impaired hepatic synthesis of clotting factors helps to explain the tendency towards severe bleeding in alcoholics. The B vitamin deficiency, particularly thiamine, leads to not only Wernicke-Korsakoff syndrome, but to other less severe neurological disorders. And there are implications on minerals, as well... though alcohol doesn't affect absorption directly, alcoholism decreases calcium absorption due to fat malabsorption, decreased magnesium levels due to decreased intake, increased urinary excretion, vomiting and diarrhea, iron deficiency related to gastrointestinal bleeding, and zinc deficiencies due to malabsorption or losses related to deficiencies of other minerals. The magnesium deficiency, which is very common in alcoholics, can in itself cause calcium deficiency. - Nunh-huh 11:23, 23 March 2008 (UTC)

[edit] Calcium Chloride re Dehumidifier

Is it possible to reuse the calcium chloride that has absorbed moisture from the air by heating the calcium chloride to release the water. Or is this possibly a dangerous experiment.

Yes - put in oven at more than 100C. This is safe, do not eat, do not inhale and dust from dried CaCl2.87.102.16.238 (talk) 14:00, 23 March 2008 (UTC)
There is one product I have seen in stores which apparently contains this chemical, and which has an indicator which changes color when the chemical has absorbed all the water it is designed to. Then you plug it into an electric outlet and a built in heating element dries it out for re-use. Edison (talk) 17:59, 23 March 2008 (UTC)

[edit] Black Hole Question

If a black holes "gravity feild" has settled into static equillibrium how do black holes merge and thier gravity merge along with it? Do the fields remain static and just reinforce eachother? I'm confused.11341134a (talk) 16:50, 23 March 2008 (UTC)

I don't think a black hole can be in perfectly static equilibrium because of Hawking radiation. But even disregarding that, saying that a thing is in "static equilibrium" usually means assuming no outside influences (like being hit by a black hole). --Allen (talk) 20:54, 23 March 2008 (UTC)
A system of objects interacting only through gravitational forces can never exist in a stable static equilibrium (except in the trivial cases of there being only one object, or every object occupies the same position and has equal velocity). Someguy1221 (talk) 03:39, 24 March 2008 (UTC)

[edit] The Cat's Brain Compared to a Human's Brain

Do you know of some such website that will let me compare a cat's brain to a human's brain? --209.226.138.43 (talk) 17:56, 23 March 2008 (UTC)

Not really, but our articles on cat intelligence and human brain might help. --Allen (talk) 18:18, 23 March 2008 (UTC)
Check out [[2]], produced by U Wisconsin, U Michigan, and the National Museum of Health and Medicine (USA). Vance.mcpherson (talk) 18:55, 27 March 2008 (UTC)

[edit] Why The Sky Is Blue?

I heard from a friend that the sky is blue because of the colour being reflected off all the water in the world.Can somebody verify that? (and no I am not doing a science project,I just really want to know) -- 209.226.138.43 (talk) 18:12, 23 March 2008 (UTC)SilverLeaf

No. See Diffuse sky radiation. --Allen (talk) 18:15, 23 March 2008 (UTC)
Hi. By the way, I'm not sure, but I think part of the reason why water (usually) appears blue is because it reflects the blue sky (either that or there is oxygen in water which scatters light). Thanks. ~AH1(TCU) 18:18, 23 March 2008 (UTC)
Here's something from the Library of Congress about why the ocean is blue. --Allen (talk) 18:25, 23 March 2008 (UTC)
We actually have an article on the Color of water. Someguy1221 (talk) 04:52, 24 March 2008 (UTC)
It doesn't talk about ice, though. If you see a big chunk of ice, like an iceberg or the face of a glacier, it may be brown/gray/black from dirt or it may be white from air bubbles or from snow cover, but in areas where none of these cases is true, you see its true blue color,which can be startlingly strong. --Anonymous, 22:57 UTC, March 24, 2008.
Ah, but in another thread below, someone mentions Blue ice (glacial), which does cover this. I've proposed a merge. --Anon, edited 23:28 UTC, March 25.
Actually, pure water absorption spectrum shows an increased absorption at 600 nm and longer wavelengths (just google "liquid water visible absorption spectrum" - there are plenty of references, but some require subscription for the respective scientific journals). Simply speaking, pure water absorbs red light stronger than yellow, green, blue, and violet light. Thus, white light passing through water loses its red component, and looks "anti-red", that is, blue to the human eye. Actually, violet light is also absorbed a bit stronger, so greenish-blue may be a more accurate description. This is for pure water; any dissolved or suspended impurities may change the perceived water color further. --Dr Dima (talk) 18:38, 23 March 2008 (UTC)
Think about this: if you shine a white light (like a flashlight) on a body of water at night, it still looks blue, right? But there isn't enough intervening air to filter out the red wavelengths in the light, so it must appear blue because the water is absorbing those wavelengths. « Aaron Rotenberg « Talk « 04:49, 24 March 2008 (UTC)
I can't imagine a flashlight producing enough light to be able to see this color. Have you actually done this? --Anonymous, 23:03 UTC, March 24, 2008.
think of it this way; the blue you see in the sky is the blue which is missing from the red and yellow and orange sunset or sunrise for people elsewhere at the same time. Gzuckier (talk) 18:48, 25 March 2008 (UTC)
In short, the sky is blue because air is blue. If you look at the earth from space you can see how very blue it is. --superioridad (discusión) 05:39, 27 March 2008 (UTC)

Rayleigh theorized that the degree of scattering of light is inversely proportional to wavelength of light. (raised to its fourth power) Hence blue, which is the shortest wavelength, is scattered the most and the sky appears blue. (Violet has the shortest wavelength in the spectrum but our eyes are more sensitive to the color blue)

[edit] FingerPrints

Why are there no 2 fingerprints alike? SilverLeaf209.226.138.43 (talk) 18:29, 23 March 2008 (UTC)

See Fingerprint#Friction Ridges. --Dr Dima (talk) 18:42, 23 March 2008 (UTC)
Also, try this Google search for more information about stochastic pattern formation and fingerprints. By the way, when editing Wikipedia, try not to start a line with spaces; it has odd formatting effects. Also, you can search for articles by typing words into the "search" box to the upper left of any page. --Allen (talk) 18:48, 23 March 2008 (UTC)

The thing I also wonder about is how permanent are fingerprints really? Some years ago I had a skin ailment that affected my fingertips (among other areas). For a time, several of my fingertips had a very smooth, taut appearance with no discernable ridges. Later, when things healed, the ridges returned, but I've always wondered with the ridges that returned actually had the same pattern as before or whether the ridges were regenerated in a different pattern than previously. Since I don't have any record of my previous fingerprints, I have no way of knowing. So how persistent are fingerprint patterns relative to diseases and physical disturbances that might temporary remove the outward manifestation of ridges? Dragons flight (talk) 19:10, 23 March 2008 (UTC)

This Google search turns up some sources like this one suggesting that they do grow back the same after physical disturbances, unless there is too much scar tissue. But I haven't looked closely enough to see if there's info on diseases, or on what mechanism preserves the original pattern. --Allen (talk) 19:31, 23 March 2008 (UTC)

[edit] Does water "go off"?

When I buy water in a bottle from the mall it has an expiration date, but I can't see why if its kept in sealed bottle you can't drink it in 100 years time. Does it go gor something?

Here is a response to a person asking the same question: http://www.madsci.org/posts/archives/aug2000/966882443.Ch.r.html
Basically, the substances that makes up the container will also leach into the water, creating unpleasant tastes. --Bowlhover (talk) 19:35, 23 March 2008 (UTC)
See Bill Nye the Science Guy Nothing444 20:00, 23 March 2008 (UTC)
Why? SpinningSpark 20:16, 23 March 2008 (UTC)
Because it's too expensive to use substances for the bottle that don't solve into the water. --85.179.24.245 (talk) 15:35, 24 March 2008 (UTC)
What about simple glass? Vranak (talk) 17:10, 24 March 2008 (UTC)
My "why?" was addressed to N444, ie what was the point of the link provided which as far as I can see is totally irrelevant. I was not referring to the question of the container material. SpinningSpark 18:56, 24 March 2008 (UTC)
Ahh. Vranak (talk) 19:46, 24 March 2008 (UTC)
I guess unless it's sterile water in a sterile container, in time bugs will grow. Julia Rossi (talk) 00:31, 24 March 2008 (UTC)
I don't agree. They would need something to eat in order to grow. StuRat (talk) 02:50, 24 March 2008 (UTC)
I can't pin down the study right now but slime mould is commonly found in bottled water beyond a certain age. I suppose trace nutrients are all they need. Franamax (talk) 02:57, 24 March 2008 (UTC)
This[3] and the article anaerobic bacteria is starting to make tap water look very good. Julia Rossi (talk) 03:19, 24 March 2008 (UTC)
Stagnant does not mean 'closed in a bottle', stagnant means just 'standing'. --85.179.24.245 (talk) 15:37, 24 March 2008 (UTC)
To grow stuff in water, you need – at a minimum – a source of energy and a source of carbon. (Strictly speaking a number of trace minerals are also necessary, but to a limited extent those can be scavenged from the original source of contamination, and many are present at some concentration in the water anyway.) A sealed bottle of water contains no carbon source; there's no raw material for new bugs, so no growth occurs. (If the cap is loose, atmospheric carbon dioxide will provide carbon.) Energy can be drawn from chemical sources (sugars, proteins, or other water contaminants) but these are rare in bottled water. The usual energy source is light, which will drive photosynthesis. Since abiogenesis is unlikely in a water bottle, we also need some initial source of contamination: fungal or algal spores or the like. Most bottled water bottles (when new) are pretty sterile, they shouldn't contain any stuff that will grow.
The picture changes when you look at people who reuse and refill their bottles. biofilms tend to build up in these containers, and they are supplied with ample fresh air and light over time. (That may be what Franamax was thinking of in his comments above).
I would guess that the concern with long-stored bottled water is due to taste or leached chemical contaminants as noted above; unopened factory-packaged bottles should contain no biological contaminants, and – unless the water were badly tainted – those organisms would be too starved to grow even if they were present. TenOfAllTrades(talk) 15:58, 24 March 2008 (UTC)
Water bottles are made of plastic. Isn't that a source of carbon? — DanielLC 16:30, 24 March 2008 (UTC)
I was thinking along the lines of this and the discussion just above the figure. Note they're referring to mineral water which is a little different than regular bottled water. I'm not sure if I was referring only to the NRDC study, I recalled something more specifically along the lines of 30% of bottles with slime mold (which is a particularly resilient animal) after 6 months, but I can't find the specific ref. Cool and dark storage would be important in avoiding contamination of any kind, whether it's chemical leaching or biologic growth. Franamax (talk) 16:37, 24 March 2008 (UTC)

[edit] Snake venom - quick question

In general, is a poisonous snake's venom effective against another snake of the same species? --Kurt Shaped Box (talk) 21:07, 23 March 2008 (UTC)

Snake_venom#Among_snakes might be of some use. bibliomaniac15 Midway upon life's journey... 21:53, 23 March 2008 (UTC)
My understand is "usually, yes." Even snakes that eat other snakes are not often immune to snake venom, it's just the difference between digesting venom and having it injected intravenously. But I'm no herpetologist. That particular article section sure has a lot of "citation needed" marks. --Captain Ref Desk (talk) 22:47, 23 March 2008 (UTC)

[edit] Eggs?

What are the brown things?
What are the brown things?

Can anyone identify the brown things in the picture? They were found recently on the lights left outside for a few months near Houston, TX. anonymous6494 22:49, 23 March 2008 (UTC)

They look like aphid eggs to me. —Steve Summit (talk) 00:17, 24 March 2008 (UTC)
Aphids are viviparous, they look a bit like eggs of a lepidoptera of some description. Compare with these. [4] Richard Avery (talk) 08:42, 24 March 2008 (UTC)


[edit] Bronner's liquid soap turns white when cold

Why? —Tamfang (talk) 23:59, 23 March 2008 (UTC)

It's just a guess, but oils often do that when they solidify. StuRat (talk) 02:47, 24 March 2008 (UTC)
I was about to guess the same thing. And our article on E. H. Bronner mentions that Dr. Bronner's is castile soap, containing made from vegetable oils. And many vegetable oils turn white when they're cold, due to partial solidification, as StuRat said. I don't know if the saponified oils in liquid soap "freeze" to milkiness in the same way, but it seems vaguely plausible. —Steve Summit (talk) 05:16, 24 March 2008 (UTC) [edited 01:45, 25 March 2008 (UTC)]
The critical micelle concentration is often temperature dependent. You may be observing a phase change where the soap molecules go from a clear, "dissolved" form to a cloudy, structured form. It's hard to say for certain, as the CMC depend heavily on the identity of the amphiphile, and when you have a mix of amphiphile types (like in standard grade soap), it get complicated fast.-- 128.104.112.85 (talk) 21:10, 25 March 2008 (UTC)